/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * Neither the name of the HISP project nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.hisp.dhis.common;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.apache.commons.lang3.BooleanUtils;

/**
 * @author Morten Olav Hansen <mortenoh@gmail.com>
 */
public final class PagerUtils
{
    public static <T> List<T> pageCollection( Collection<T> col, Pager pager )
    {
        return pageCollection( col, pager.getOffset(), pager.getPageSize() );
    }

    public static <T> List<T> pageCollection( Collection<T> col, int offset, int limit )
    {
        List<T> objects = new ArrayList<>( col );

        if ( offset == 0 && objects.size() <= limit )
        {
            return objects;
        }

        if ( offset >= objects.size() )
        {
            offset = objects.isEmpty() ? objects.size() : objects.size() - 1;
        }

        if ( (offset + limit) > objects.size() )
        {
            limit = objects.size() - offset;
        }

        return objects.subList( offset, offset + limit );
    }

    public static boolean isSkipPaging( Boolean skipPaging, Boolean paging )
    {
        if ( skipPaging != null )
        {
            return BooleanUtils.toBoolean( skipPaging );
        }
        else if ( paging != null )
        {
            return !BooleanUtils.toBoolean( paging );
        }

        return false;
    }

    private PagerUtils()
    {
    }
}
